Abstract
The host-parasite relationship involving many factors is easily understood by observing a simple infection system from which the involved factors are possibly excluded. Furthermore, it is possible to study each role of the factors influencing the infection by utilizing the thus simplified infection system. It would be expected that, in the host-parasite relationship, the factors in the liquid component existing between the host and parasite might play important roles in susceptibility of the host against the parasites and in the completion of infection. The authors (1) investigated the effects of the sera on the phagocytosis in the course of cellmycobacteria infection system by using the L cell which was derived from mouse fibroblast.This present paper is to report the effect of old tuberculin of BCG on the course of infection of BCG to the L cell because it is conceivable that the effects of metabolates of the parasites on the phagocytosis or invasion to the cell are important.
